Low-profile miniature disk cartridge

ABSTRACT

A disk cartridge for use in a miniature drive. The drive is usable in a variety of small computer devices. As such it is constrained in both height, width and length. Preferably, the drive is of a PCMCIA size, preferably type II. The cartridge for use therein is less than about {fraction (1/10)} inches high and less than about 2 inches wide.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a cartridge based data storage systemin which a flexible magnetic disk is disposed within a cartridge shell.More particularly, the invention relates to a low-profile miniature diskcartridge.

[0002] Microprocessors and supporting computer technologies are rapidlyincreasing in speed and computing power while decreasing in cost andsize. These factors have led to the broad application of microprocessorsto an array of electronic products, such as hand-held computers, digitalcameras, cellular phones and the like. All of these devices have, ineffect, become computers with particular application-specificattributes. For this new breed of computer products, enormousflexibility is gained by the ability to exchange data files and storecomputer software.

[0003] A variety of proprietary storage devices have been used incomputer products. For example, hand-held computers have used integratedcircuit memory cards (“memory cards”) as the primary information storagemedia. Memory cards include memory storage elements, such as staticrandom access memory (SRAM), or programmable and erasable non-volatilememory, such as “flash” memory. Memory cards each are typically the sizeof a conventional credit card and are used in portable computers inplace of hard disk drives and floppy disk drives. Furthermore, memorycards enhance the significant advantages of the size, weight, andbattery lifetime attributes of the portable computer and increaseportability of the storage media. However, because of the limited memorydensity attainable in each memory card and the high cost of thespecialized memory chips, using memory cards in hand-held computersimposes limitations not encountered in less portable computers, whichtypically use more power-consuming and heavier hard and floppy diskdrives as their primary storage media.

[0004] Other of these computer products, such as the digital camera,have employed miniature video disks as the storage media. For example,U.S. Pat. No. 4,553,175 issued Nov. 12, 1985 to Baumeister discloses adigital camera configured to store information on a magnetic disk. InBaumeister, a signal processor receives signals representative of apicture from a photo sensor. Those signals are recorded on a magneticdisk for later processing. Unfortunately, the video disk storage productprovides limited storage capacity. For that and other reasons (e.g.,power consumption and cost), the video disk has not been used in othercomputer products. As a result, interchanging data from one of thesedigital cameras with other computer products, such as a hand-heldcomputer, is not readily achieved.

[0005] Miniature hard disk drives have also been suggested for use inportable computer products. For example, U.S. Pat. No. 5,469,314 issuedNov. 21, 1995 to Morehouse et al. discloses a miniature hard drive foruse in portable computer applications. In Morehouse, a hard disk driveis described that is approximately 50 mm in diameter. While addressingmany of the problems presented by storage requirements in portablecomputers, the obvious problem of removability of the storage media isstill present.

[0006] Similar to a standard size cartridge, the miniature cartridgecontains a flexible magnetic disk disposed within a hard outer shell.Such a standard size cartridge is disclosed in U.S. Pat. No. 4,445,157(Takahashi). The Takahashi patent is generally directed to a diskcassette that contains a flexible magnetic disk having a center core(i.e., a hub) and an apparatus for reading and recording information onthe flexible magnetic disk. The disk cassette comprises a flexible diskattached to a hub. The disk and hub assembly are sandwiched between anupper cover and a lower cover.

[0007] Thus, there is a need for an miniature disk cartridge for usewith portable devices.

SUMMARY OF THE INVENTION

[0008] In accordance with the present invention a mini-cartridge isprovided for mini drives in a plurality of hand-held devices whichgenerate signals representing different functions performed by differentclasses of the devices. For example, the devices include digitalcameras, electronic books, global positioning systems, personal digitalsystems, portable games and cellular phones. Each of these devices has amini drive for writing signals and reading signals representing thefunctions to and from a magnetic medium in the mini-cartridge. In thisway, signals representing the diverse functions performed by thedifferent classes of devices are recorded on the mini-cartridge. Thehand-held devices incorporating the present invention provide and createa single means of capturing, moving and storing information acrossmultiple products.

[0009] The present invention is directed to a miniature data storagedevice and disk cartridge for use in a drive. The drive is usable in avariety of small computer devices. As such it is constrained in bothheight, width and length. Preferably, the drive is of a PCMCIA size,preferably type II. The cartridge for use with the drive comprises anouter shell having a spindle access opening and a head access opening. Asubstantially flexible medium is rotatably disposed within the outershell, and a hub is connected to the medium proximate the center. Theouter shell has a thickness less than about 0.10 inches and a width lessthan about 2 inches.

[0010] The disk cartridge further comprising a shutter for selectivemovement over the head access opening, The outer shell comprises sheetsteel and the shutter comprises aluminum.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing summary, as well as the following detaileddescription of the preferred embodiments, is better understood when readin conjunction with the appended drawings. For the purpose ofillustrating the invention, there is shown in the drawings an embodimentthat is presently preferred, it being understood, however, that theinvention is not limited to the specific methods and instrumentalitiesdisclosed. In the drawings:

[0012]FIG. 1 is a diagram of the interchangeable mini-cartridge of thepresent invention, including a plurality of devices each having a minidisk drive, and including a caddy to adapt the mini-cartridge to afull-size drive of a host computer;

[0013]FIG. 2 is a top plan view of a disk drive according to the presentinvention;

[0014]FIG. 3 is an isometric view of a cartridge for use with the driveof FIG. 1;

[0015]FIG. 4 is a top plan view of the cartridge of FIG. 2;

[0016]FIG. 5 is a bottom plan view of the cartridge of FIG. 2;

[0017]FIG. 6 is a side elevation view of the cartridge of FIG. 2;

[0018]FIG. 7 is an exploded view of the cartridge of FIG. 2;

[0019]FIG. 8 is a partially exploded view of the cartridge of FIG. 2showing an internal shutter shell subsystem;

[0020]FIG. 9 is a top plan view of the cartridge of FIG. 2 with theupper shell half removed to reveal the operation of the shutter shell;

[0021]FIG. 10 is another top plan view of the cartridge of FIG. 2 withthe upper shell half removed to reveal the operation of the shuttershell;

[0022]FIG. 11A-11E are illustration of the operation of shutter shell 16in conjunction with the drive of FIG. 2;

[0023]FIG. 12 is a bottom isometric view of the cartridge of FIG. 2showing the lateral freedom of movement of the hub;

[0024]FIG. 13 is a cross section of the disk of FIG. 12 along the lines13-13;

[0025] FIGS. 14A-14D show cross sections of the cartridge and drive ofFIGS. 11A-11D along the lines 14-14 in various stages of insertion thecartridge into a disk drive;

[0026]FIG. 15A shows an isometric view of the load ramp of the presentinvention;

[0027]FIG. 15B shows the arms opened during media insertion to preventdamage to the media;

[0028]FIG. 15C shows the arms closed after media is fully inserted intothe drive;

[0029]FIG. 15E shows the heads loaded onto the load ramp and compressinga bias spring;

[0030]FIG. 16 is an isometric view of the interior of a shutter shelland liner assembly showing the relative location of a media distortionneutralizer.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0031] The present invention provides a data storage cartridge for usewith a removable media type of disk drive. Throughout the description, apreferred embodiment of the invention is described in connection with aparticular sized and shaped disk cartridge. However, the disk cartridgedimensions and shape are presented for exemplary purposes only.Accordingly, the mechanism should not be limited to the particularcartridge embodiment shown as the invention contemplates the applicationto other cartridge and drive types and configurations.

[0032]FIG. 1 shows a plurality of devices 100 which generate signalsrepresenting different functions performed by different classes of thedevices. For example, the global positioning system 100 a can generatesignals representing navigational position. Electronic book 100 b,digital camera 100 c, personal digital assistant (PDA/Palmtop) 100 d,portable game 100 e, cellular phone 100 f, and laptop computer 100 geach generate signals representing the function performed by thatparticular device. Each of these devices has a miniature disk drive 50for writing the signals and reading the signals from a magneticrecording medium so that diverse functions performed by differentclasses are recorded on the devices, i.e. a drive 50 a for globalpositioning system 100 a, a drive 50 b for electronic book 100 b, adrive 50 c for digital camera 100 c, a drive 50 d for PDA/palmtop 100 d,a drive 50 e for portable game 100 e, a drive 50 f for cellular phone100 f, and a drive 50 g for laptop computer 100 g.

[0033] A mini-cartridge 10 has a magnetic recording medium on which thesignals from the devices are recorded. Mini-cartridge 10 is compatiblewith the mini drives 50. Standard file formats maintain compatibilitybetween devices 100. In the preferred embodiment, drives 50 are sized tofit within a PCMCIA form factor, preferably PCMCIA type II or type III,more preferably type II. These form factors is commonly used in portablepersonal computers. For example, PCMCIA type II form factor is commonlyused for a modem connection of a notebook computer. PCMCIA type II formfactor is quite small so that miniature drive 50 readily fits into allof the portable, hand-held devices shown in FIG. 1. The miniature drive50 is insertable into and removable from the device just as the PCMCIAmodem is insertable into and removable from the PCMCIA slot of anotebook computer. Alternatively, the drive 50 could be hard wired,i.e., built-in, to the device. In both cases, the device generates adigital function signal which is connected to the magnetic heads of thedrive so that the digital function signal can be written on the magneticmedium of miniature cartridge 10. As an example, a digital functionsignal representing a picture taken in a digital camera 100 c isrecorded on a cartridge 10. This digital function signal can then beread by other classes of devices when the cartridge 10 is inserted intothe respective other device.

[0034]FIG. 2 is a top view of a disk drive 50 with its top cover removedfor clarity. Drive 50 accepts a removable disk cartridge 10 (shown inphantom) for reading and storing digital information. Drive 50 comprisesa chassis 57, an actuator 56 (preferably a rotary actuator), includingan opposing pair of load beams 44 having a read/write head 54 disposedat the end of each load beam, a load ramp 47, a spindle motor 53 and aspindle 40, and a shutter opening arm (not shown). The operation of diskmounting to spindle 40 is described more fully below. A disk cartridge10 can be inserted into the front of the drive in the directionindicated by the arrow. During insertion, cartridge 10 slides linearlyalong the top surface of chassis 57 and spindle motor 53 for engagementwith the read/write heads 46.

[0035] FIGS. 3-6 are isometric, top plan, bottom plan, and sideelevation views of a miniature disk cartridge 10 that embodies aspectsof the present invention. Miniature disk cartridge 10 has a number ofdifferences from a full-size cartridges, such as the well-known 1.44megabyte 3.5″ floppy disk cartridge and the well-known ZIP diskcartridge) that prevent the miniature disk cartridge 10 from operatingdirectly in a full-size drive. Perhaps, the most obvious of thesedifferences is size. Disk cartridge 10 has a much smaller form factorthan a full-size drive cartridge. Whereas a full size drive cartridge isabout 4″ square and ¼″ high, a mini-cartridge less than about 2″ widesquare and about {fraction (1/10 )}″ high. In particular, disk cartridge10 has a width w preferably in a range of about 49 (1.9″) to 51 mm (2″),most preferably about 50.1 mm, a length l about 50 to 52.5 mm long,preferably about 51.8 mm, and a thickness h less than about 2 mm (about{fraction (1/10)}″) thick, most preferably 1.95 mm. A large wedgedshaped disk access opening 418 is disposed in the front portion of diskcartridge 10 to provide selective access to the media of cartridge 10.Disk cartridge 10 comprises a flexible magnetic disk 14 (partially shownin FIG. 5) and a disk media hub 12. A driving access hole 218 providesan opening in cartridge 10 for drive spindle 40 (see FIG. 2) to engagehub 12 and drive flexible disk 14 past opposing read write heads 54(also shown in FIG. 2). Hub 12 is sized slightly smaller than drivinghole 218 b, and as best shown in FIG. 4, hub 12 projects downwardly fromcartridge 10. Cartridge 10 also has a side cut-out 34 and abutmentsurface 35. As explained more fully below, cut-out 34 and abutmentsurface 35 engage a sliding lever during cartridge insertion andejection. Cut-out 34 functions to retain cartridge 10 in drive 50 andensure proper cartridge insertion while abutment surface 35 provides aflat surface for engagement and spring loading of sliding lever.

[0036] Referring also to FIG. 7, an exploded view of cartridge 10 isprovided to more clearly show cartridge 10 interior components.Cartridge 10 comprises top and bottom cartridge shell halves 18 a and 18b, respectively, a rotary shutter shell having upper and lower halves 16a and 16 b, respectively, upper and lower shutter shell liners 15 a and15 b, respectively, a shutter pivot post 20, a shutter spring mechanism22, and a shell stabilizer 24.

[0037] Cartridge 10 is about half the thickness of the well-known 3.5inch floppy disk. As a result convention removable cartridge shellmaterials cannot be used to construct cartridge 10. Plastics, such asthose used in the well-known 3.5 inch floppy disk, would either be toothick or not strong enough if manufactured with the desired thickness.To manufacture a thin cartridge, such as cartridge 10, all of thecomponent materials must be as thin as possible while providingstructural support that will withstand the rigors of everyday use. Forexample, cartridge shell halves 18 a and 18 b are formed from a thinsheet material preferably about 0.1854 mm thick. To provide thestructural support, the shell is preferably made from a sheet metal.Preferably the metal is sheet steel, more preferably stainless steel,and most preferably series 300 stainless steel. Cartridge shell halves18 a and 18 b are preferably cut from a sheet of steel in a stampingoperation which forms the turned edge portions 118 a and 118 b, providesthe cutouts such as the driving hole 218 b in the bottom cartridge shellhalf 18 b, post hole 218 a in the top cartridge shell half 18 a, mediaaccess openings 418 a, 418 b, and so on.

[0038] Shutter shell halves also must meet strict thicknessrequirements. As such, shutter shell 16 a and 16 b are formed from athin sheet material. The sheet material is preferably a sheet metal. Thesheet metal is preferably thin sheet aluminum, preferably 5052 aluminum,more preferably in a half-hard condition. The sheet aluminum ispreferably about 0.1854 mm thick. Shutter shell halves are alsopreferably cut from a sheet of aluminum in a stamping operation whichforms upstanding rim 116 a in top shutter shell half 16 a, upstandingrim 116 b in the bottom shutter shell half 16 b, and cuts driving hole316 b in the bottom of shutter shell half 16 b, pivot hole 316 a in thetop shutter shell half 16 a, and media access openings 416 a, 416 b inshutter shell halves 16 a and 16 b.

[0039] Upper shutter shell half 16 a has a media distortion neutralizer11 disposed on the inner surface 216 a of shutter shell half 16 a.Distortion neutralizer 11 is located proximate the apex region of wedgeshaped opening 416 a. As described in further detail below, distortionneutralizer aids the planarity of media 14 as it approaches head loadramps during disk cartridge 10 insertion into drive 50. Distortionneutralizer provides a raised surface on upper shutter half 16 a.Preferably the distortion neutralizer is formed directly on the surfaceof shutter half 16 a, but could also be formed as a separate piece andattached by glue, welding, or the like.

[0040] Liners 15 a and 15 b are attached to shutter shell halves 16 aand 16 b. Liner 15 a is attached to inside surface 216 a of shuttershell half 16 a; whereas liner 15 b is attached to inside surface 216 bof shutter shell half 16 b. As described in detail below, disk media 14rotates within the shutter shell and not the cartridge shell.Accordingly, unlike other known cartridges wherein the liners aretypically attached to the inside of the cartridge shell, liners 15 a, 15b are attached to the inside surface of shutter shells 16 a, 16 b.

[0041] Liners 15 a and 15 b are preferably attached via an adhesive,more preferably a pressure sensitive adhesive. Liners 15 a and 15 b arecut to the shape of the surface to which they will be attached (i.e.,216 a, 216 b) from a sheet of liner material. The liner material ispreferably 100% polyester, more preferably Veratec 141-620 availablefrom Data Resources Group in Walpole Mass. The liner material has athickness preferably in the range of about 3.35 mils to about 3.8 mils,more preferably about 3.35 mils.

[0042] Stabilizer 24 is a substantially U-shaped spacer positioned inthe rear portion of cartridge 10 and between upper and lower cartridgeshell halves 18 a and 18 b. Rear cartridge shell tabs 318 a and 318 bextend rearwardly from upper and lower shell halves 18 a and 18 b andwrap around stabilizer 24. Therefore, when cartridge 10 is assembled, aportion of stabilizer 24 extends into and between the shell halves 118 aand 18 b and portions of stabilizer 24 protrude from joined upper andlower shell halves 18 a and 18 b. The protruding portions of stabilizer24 form portions of the outer contours of cartridge 10. In particular,stabilizer 24 forms cartridge rear corners 24 a and 24 b and forms rearportion 24 c.

[0043] Stabilizer 24 is formed of a lightweight rigid material such asplastic. More preferably, stabilizer 24 is formed of high impactpolystyrene. It is formed from any one of the well-known plastic formingprocesses, such as injection molding. Stabilizer 24 provides dimensionalstability and rigidity to cartridge 10, thereby minimizing cartridgedeformation during mishandling, twisting, and so on.

[0044] Shutter spring mechanism 22 comprises a guide wire 23 and a roundhelical compression spring 21 that is slid over guidewire 23. Shutterspring mechanism 22 is fixed to stabilizer 24 at the ends of guide wire23. The ends seat in channels 124 a and 124 b that are formed into theends of U-shaped stabilizer 24. The operational details of shutterspring mechanism 24 are described in further detail below in connectionwith the description of cartridge opening and closing.

[0045] Flexible magnetic disk 14 is formed of a thin polymer film, suchas MYLAR, and has a thin magnetic layer uniformly dispersed on the topand bottom surfaces thereof. The magnetic layer makes the flexible disk14 susceptible to magnetic flux and enables the storage of digital datawhen the disk surface is brought into magnetic communication with amagnetic transducer of the type commonly found in disk drives. Disk 14is generally circular with a circular hole proximate the center of disk14. Disk 14 has a radius r in a range of about 20 to 25 mm, andpreferably about 23.25 mm. Disk 114 has concentric tracks 114 thatprovide the formatting of disk 14 to store digital information. Disk 14contains a high density of tracks per inch (TPI), preferably in a rangeof about 2900 to about 3100 TPI, more preferably disk 14 contains about3050 TPI. This high track density, which incidentally is much high thatthe common 1.44 megabyte floppy TPI of about 10 TPI, allows therelatively small disk 14 to store at least 40 megabytes of digital data.

[0046] Media hub 12 is essentially donut shaped and comprises a ferrousmaterial such as steel, preferably stainless steel. The surface finishis about 8 micro inches to reduce sliding function. Hub 12 comprises abore or hole 12 a proximate the center, peripheral outer edge 12 b andinner ring surface 12 c. Inner ring 12 c has an outer angled edge and asubstantially flat bottom surface. Outer peripheral edge 12 b is alsoangled. Media hub 12 is firmly secured to disk 14 such that the centerof hub 12 is aligned proximate the center of disk 14. Media hub 12 ispreferably attached to disk 14 via a well-known adhesive process. Thedisk and hub assembly are rotatably disposed between upper and lowercartridge shutter shell halves 16 a, 16 b. Hub 12 is disposed in spindleaccess hole 316 b of spindle access opening 316 c of lower shutter shell16 b and spindle access hole 218 b of lower cartridge shell 18 b. Asdescribed in further detail below, the protrusion of hub 12 from shuttershell 16 and an cartridge shell 18 enhances coupling to a rotationalpower source, such as that provided by a drive spindle, when cartridge10 is within drive 50 and acts a restraint on lateral movement of disk14 when the cartridge is removed drive 50.

[0047] As shown by FIGS. 7 and 8, shutter halves 16 a and 16 b snaptogether to form shutter shell 16, which houses media 14 and shutterliners 15 a and 15 b (not shown in FIG. 5) which are attached to theinner surfaces of shutter shells 16 a and 16 b respectively. Thecomplete shutter assembly 28 is pivotally attached to top shell 18. Hub12 is attached to media 14 and protrudes through drive access hole 316 bin shutter shell 16 b. Accordingly, when cartridge 10 is inserted andoperating in drive 50, media 14 rotates within shutter shell 16. As bestappreciated from Figure unlike other disk cartridges which do not rotatewithin the shutter but which rotate within cartridge shell 18. Pivotpost 20 attaches shutter assembly 28 to upper shell half 18 a byattaching the top portion 20 to pivot hole 218 b via shutter pivot hole316. Pivot post 20 is fixedly attached to top shell cartridge 18 a whileleaving an offset space between and around post portion 20 a and shutterpivot hole 316 a.

[0048] The use of an internal shutter shell provides several advantagesover other internal shutter designs. Among the advantages are improvedcartridge 10 rigidity, improved disk 14 aerodynamics, and improvedshutter control. The improved rigidity results from cartridge 10 havingtwo layers of shell material (shutter 16 and shell 18) to guard againstmishandling. The improved disk 14 aerodynamics result from the fact thatspace within which disk 14 rotates is completely controlled and free ofdisturbances caused by other internal mechanical features. For example,in other internal shutter designs, the retracted shutter only covers aportion of the spinning disk thereby increasing the likelihood of airflow disturbances. The final example of the benefits of shutter 16 ofthe present invention is improved shutter opening control. Shutterstypically have a biasing mechanism to close the shutter. In the presentshutter design, a spring 21 provides such a bias. Here, spring 21 can belocated in the rear of the cartridge 10 and still control the operationof shutter 16.

[0049] When shutter assembly 28 is complete, media 14 is exposed atmedia access opening 416. However, and as described more fully below,media 14 within cartridge 10 is only accessible from outside ofcartridge 10 when shutter access opening 416 aligns with cartridge shellaccess opening 418. In such an alignment, shutter shell 16 moves to afirst position so that the openings 416, 418 completely overlap thereby“opening” cartridge 10. When the cartridge shell access opening 416 andcartridge shell access opening 418 are misaligned, shutter shell 16moves to a second position such that the openings 416, 418 do not overlap thereby “closing” cartridge 10, shielding media 14 from ambientcontaminants.

[0050]FIGS. 9 and 10 illustrate the “opening” and “closing” operation ofshutter shell 16 with spring mechanism 22. FIG. 6 is a top plan view ofcartridge 10 in the closed position with upper cartridge shell 18 aremoved for clarity. FIG. 7 is a top plan view of cartridge 10 in theopen also with upper cartridge shell 18 a removed for clarity. Themotive force for biasing shutter 16 toward the closed position isprovided by compression spring 23 in an arcuate path. As noted above,compression spring 21 is slid over arcuate guidewire 23, which isattached to the ends of U-shaped stabilizer 24 in slots 124 a and 124 b.After attachment of compression spring 23 onto guidewire 21, spring 23follows the arcuate path established by guidewire 21. Other structuresare possible for forming an arcuate spring path. For example, an arcuatechannel cut into the stabilizer 24 would also provide an arcuate pathfor spring 23. However, the use of guidewire 23 is preferred because itfacilitates construction of cartridge 10 by improving the handling ofspring 21. That is, spring 21 easily conform to the shape of wire 23which is then attached to stabilizer 24.

[0051] Shutter shell 16 has an extending tab 17 that couples antranslates a force between shutter 16 and spring 21. Tab 17 ispreferably formed into shutter 16 but could alternately be attached toshutter shell 16 as a separate part such as by welding. Tab 17 extendsoutwardly from shutter shell 16 so as to extend into the spring path,overlapping guide wire 23. When cartridge 10 is in the closed position,compression spring 21 engages tab 17 biasing shutter 16 toward theclosed position. To open cartridge 10, a counterclockwise rotationalforce is applied to shutter shell 16 (from the perspective of FIGS. 6and 7) against the bias of spring 21, thereby compressing spring 21.When the rotational force is removed from shutter shell 16, spring 21biases shutter shell 16 back to the closed position.

[0052] Cartridge 10 has several features (best described with respect toFIGS. 9 and 10) that cooperate in the operation of shutter 16 inconjunction with drive 50. These features include, catch feature 516,flat nose portion 518, and retraction slot 618 (see FIG. 5 for analternate view of retraction slot 618).

[0053] Shutter catch feature 516 protrudes outwardly from the radius ofshell 16. Catch feature 516 provides two significant functions in theoperation of shutter 16: first, it provides a stop when spring 21 biasesshutter 16 toward the closed position; and second, it provides amechanism for coupling with drive 50 so that shutter 16 can be openedduring insertion into drive 50. The stop function of catch 16 operateswhen shutter 16 rotates toward the clockwise direction. When rotated tothe closed position, catch 516 engages the cartridge shell edge andthereby stops the rotation of shell 16.

[0054] Referring to FIGS. 11A-11E, the operation of shutter shell 16with drive 50 is further illustrated. Referring to FIG. 11A, cartridgeshell 18 also has a flat nose portion 518 which is adjacent to catchfeature 516 when shutter shell 16 is in the closed position. Uppercartridge shell 18 a has an overhang 718, proximate flat nose portion518, that shields catch 516 when the cartridge is not in drive 50.Shutter 16 is opened by shutter lever 48. Shutter lever 48 has a hooklike portion 48 a on its proximal end. Hook like portion 48 a has anupstanding tab portion 148 that is adapted to engage shutter shell 16.When a cartridge 10 is inserted into drive 50, upstanding tab 148engages flat nose portion 518. The relatively flat and wide upstandingtab 148 and flat nose portion 518 provide sufficient area to ensure thatlever 48 properly and reliably engages shutter 16. Additionally, flatnose portion 518 enhances the pressure angle to more easily begin therotation of shutter 16. When properly engaged, an edge of upstanding tab516 mates with catch 516.

[0055] A retraction slot 618 is cut into the lower cartridge shell 18 b.Retraction slot 618 permits the upstanding tab to retract, along withcatch 516, into cartridge shell 18 and move out of the way of the otherdrive 50 components. This ability to retract the shutter openingmechanism and catch 516 results in a larger disk access opening. FIG.11E illustrates cartridge 10 loaded fully into drive 50 with lever 48and shutter shell 16 fully retracted.

[0056] Shutter lever 48 is pivotally mounted at its distal end 48 b todrive chassis 57 proximate the front portion of drive 50. Shutter lever48 is biased by a spring (not shown) in a clockwise direction (as viewedin FIGS. 11B-11E). As a result of the bias, lever 48 pivots to apositioned proximately as shown in FIG. 11B when a cartridge 10 isabsent from drive 11.

[0057] As best illustrated in FIG. 11C, when cartridge 10 is insertedinto drive 50, the nose 518 of cartridge 10 engages shutter lever 48. Atthe point of engagement, hook end 48 of shutter lever 48 mates withcatch 516. After the shutter lever 48 has engaged shutter catch 416, theforce of insertion (supplied by the user) of cartridge 10 further intodrive 50 will cause shutter 16 to rotate in tandem with lever 48 in thecounterclockwise direction. The rotation of lever 48 against theclockwise spring bias loads the spring of lever 48. Similarly, therotation of shutter 16 against the bias of spring 21 loads shutterspring 21. Accordingly, when cartridge 10 ejects from drive 50, spring21 causes shutter 16 to snap shut and lever 48 to return to a positionproximate the position shown in FIG. 11B. FIG. 11D shows the firststages of shutter 16 rotation as cartridge 10 moves further into drive50. FIG. 11E shows the complete insertion of cartridge 10.

[0058] Shutter 16 and lever 48 disengage in essentially the reversesequence from that described above in connection with FIGS. 11A-11E.However, the ejection of cartridge 10 from drive 11 is aided by spring21 of cartridge 11. In particular, as cartridge 10 ejects from drive 50,the force of spring 21 rotates shutter 16 in the clockwise direction.The force of spring 21 causes catch 516 to impinge upon upstanding tab148. This force also causes cartridge 10 to move outwardly from drive10. Of course, this force to move the cartridge outwardly diminishes asthe shutter lever moves clockwise toward its pre-loaded position.Further details of a disk drive insertion and ejection mechanism aredescribed in co-pending patent application Ser. No. ______ (AttorneyDocket No. IOM-9720) entitled “METHOD AND APPARATUS FOR CARTRIDGEEJECTION AND OVERWRITE PROTECTION” filed Nov. 13, 1997, which is herebyincorporated by reference in its entirety.

[0059]FIG. 12 shows an isometric view of the underside of cartridge 10.Hub 12 is disposed in spindle access hole 18 d of cartridge 10. Hub 12comprises a substantially flat bottom surface 12 e, and an inner ring 12c, and an outer peripheral edge 12 b. Also shown in FIG. 12, bottomshell half 18 b has a rounded edge 218 c around drive access hole 218 b.Hub 12 and rounded edge 218 c interact to restrain lateral movement ofdisk 14 within cartridge shell 18.

[0060] Unconstrained lateral movement of disk 14 within cartridge 10could cause the edges of disk 14 to impinge upon the inner circumferenceof shutter 16. Such impingement could damage disk 14 causing data lossor worse. Referring also to FIG. 13 (a cross section of FIG. 12 alongthe line 13-13), hub 12 and attached disk 14 are free to move laterally(in the x and y plane) within cartridge 10 by the distance indicated byline 112. However, hub 12 projects outwardly from drive access hole 218b (see also FIG. 6). This projection of hub 12 is much more pronouncedthan with conventional floppy disk cartridges. The projection is sopronounced that even if hub 12 is pushed up ( in the z direction) intocartridge 10, hub 12 still projects out from drive access hole 218 b.The overall effect of the hub projection is to prevent disk 14 frommoving laterally so that its edges contact the inner circumference ofshutter 16.

[0061] During insertion of cartridge 10 into drive 50, spindle 40remains fixed and cartridge 10 slides in a fixed plane relative tospindle 40. In other words, unlike typical cartridge insertionmechanisms used in other disk drive systems, in present drive 50 andcartridge 10 there is no translation of either cartridge 10 or spindle40 in the z-axis. Accordingly, to mount hub 12 to spindle 40, hub 12undergoes z-axis translation as it slides along the top surface ofspindle motor 53 and over spindle 40. This z-axis translation of hub 12is best illustrated with reference to FIGS. 14A-14C, which presentcut-away side views of cartridge 10 and drive 50 that loosely correspondin relative position to cartridge 10 and drive 50 in FIGS. 11, alonglines 14-14.

[0062] Peripheral edge 12 b preferably forms angled outer surface thatis adapted to engage with a rounded edge of the spindle access openingduring upward translation into shell 18. The preferred angle α for theouter edge is about 45 degrees. More preferably peripheral outer edge 12b substantially forms a ring around the circumference of hub 12.However, other configurations could accomplish a similar function, suchas spoke-like or fingers of angled surfaces rather than a solid annularsurface depicted in the figure. Similarly, inner ring surface 12 c,preferably substantially ring shaped, could also comprises a differentform, for example a series of fingers. Inner ring surface 12 c also hasa preferred angle, β, of about 45 degrees.

[0063] As shown by the cut-away side views, hub 12 has a stepped sideprofile. Disk 14 is attached to the hub along a topmost surface 12 h ofhub 12. A step down from top surface 12 h is a surface 12 j, which formsthe top of peripheral outer edge 12 b. The step provides a gap 13between the hub 12 and disk 14. As is described more fully below, gap 13provides additional flexibility for vertical translation of hub 12within cartridge 10.

[0064] Spindle motor 40 has several features that are adapted tointeract with hub 12. In particular, spindle 40 includes the “z” datum40 a (provided by a raised ring), a round boss surface 40 b and aconical lead-in groove 40 c. All of these features cooperate to enableengagement and disengagement of hub 12 from spindle 40. In addition, thetop of spindle 40 is magnetically sensitized to attract and magneticallycouple hub 12 to spindle 40.

[0065] Significantly, hub 12 engagement and disengagement from spindle40 occurs without translating the plane of cartridge 10 vertically (i.e.in the z-axis direction) relative to the plane of the drive or withouttranslating the spindle motor. Consequently, the height of drive 10 canbe thinner than is possible in either a spindle or cartridge translationmethod. Instead of translating either the spindle or the cartridge, hub12 and media 14 are translated along the z-axis within shell 18 as thecartridge is translated linearly (i.e., along a plane substantiallyparallel to the x-axis) into and out of drive 50. No additional space isrequired within cartridge shell 18 to accommodate the z-axis translationof hub 12, other than space which is already available to allow disk 14to spin freely within shell 18. The present invention can even functionproperly with less interior cartridge space than that provided in acommon 3.5 inch disk cartridge.

[0066] During insertion of cartridge 10 into drive 50, as depicted inFIG. 4A, hub 12 slides on inner ring surface 12 c over the relativelyplanar profile of the bottom of chassis 57 and over the top of spindle40. The ring surface provided by inner ring 12 c provides a relativelylarge surface area for hub 12 to slide upon during insertion into drive50. This large surface area ensures that the hub slides smoothly intodrive 50. Downwardly projecting pin 20 is coupled proximate the centerof cartridge 10 to top shell portion 18 a. The downwardly projecting pin20, engages sidewall 12 a of hub 20 urging it into chassis 57.

[0067] A force applied to cartridge 10 during insertion causes pin 20 topush against the sidewall of bore 12 a. This pushing provides a force toovercome the friction between inner ring surface 12 c and chassis 57 andtop of spindle 40. As cartridge 10 reaches far enough into drive 50,inner ring surface 12 c aligns with conical lead-in groove 40 c. At thatpoint, the magnetic force provided by spindle 40 attracts and pulls hub12 into engagement with spindle 40, resulting in inner ring surface 12 cextending into conical lead-in groove 40 c. As best shown in FIG. 4B,the angles of lead-in groove 40 c and inner ring surface 12 c,preferably proximately 45 degrees, are such that hub 12 properly alignson center with spindle 40 as hub 12 is pulled into a seated position. Inparticular, inner ring 12 c forms a cone-like male surface thatcorresponds with the cone-like female opening of lead-in groove 40 c. Asthe two cone-like surfaces engage, inner ring 12 c is guided by conicallead-in groove 40 c. Moreover, the relatively large diameter of innerring surface 12 c (as measured across hub 12) and conical lead-in groove40 c ensures a highly accurate alignment of hub 12 to spindle 40.

[0068] As cartridge 10 ejects from drive 50, hub 12 disengages fromspindle 40, again, without vertical translation of cartridge 10 withrespect to drive 50 (only hub 12 and media 14 translate in the z-axis).As best shown in FIG. 4C, when cartridge 10 starts ejection from drive50, cartridge shell 18 moves outwardly from drive 50. During thisoutward movement of cartridge shell 18, hub 12 initially remains seatedon spindle 40. A force is required to cause disengagement of hub 12. Therequired force is provided by the movement of cartridge shell 18relative to hub 12. Cartridge shell 18 has downwardly projecting pin 20and rounded edge 18 c that cooperate with hub 12 to facilitatedisengagement.

[0069] Disengagement begins when pin 20 impinges on the sidewall of bore12 a. Substantially simultaneously, rounded edge portion 18 c contactsthe angled peripheral outer edge 12 b. As shell 18 continues to moveoutwardly, rounded edge 18 c slides against angled peripheral edge 12 b.The horizontal movement (along the x-axis) of rounded edge 18 c relativeto angled edge peripheral edge 12 b urges a lifting hub 12. The combinedimpingement of pin 20 and lifting of shell 18 b cause hub 12 to tiltabout datum 40 a. As hub 12 tilts, inner ring surface 12 c also tilts.When the bottom surface 12 f of inner ring 12 c clears the top 40 d ofspindle 40 hub 12 can also move begin moving outwardly with cartridge10. As hub 12 moves outwardly, angled inner ring surface 12 g engagesangled spindle lead-in groove surface 40 c. Because both surface areangled, hub 12 slides up the side of lead-in groove surface 40 c.

[0070] As best shown in FIG. 14D, when bottom surface 12 f of inner ring12 c clear datum 40 a of spindle 40, hub 12 is free to move withcartridge 10. Thereafter, pin 20 urges hub 12 to travel in tandem withcartridge shell 18. The force of pin 20 continues to drag hub 12 overthe surface of spindle motor 53 and chassis 57 until cartridge 10 hasejected from drive 50.

[0071] The stepped profile of hub 12 allows for additional headroom ashub 12 tilts within cartridge 10. That is, without a stepped hub, thetilting could cause the top of hub 12 to impinge upon the inner topsurface of shell 18 a and interfere with the disengagement of hub 12from spindle 40. Moreover, the stepped hub allows the disk 14 to flex ashub 12 is tilted during disengagement.

[0072] A best illustrated in 14A, hub 12 is translated in the z-axisdirection during cartridge 10 insertion into drive 50. As a result, disk14 is push upward to the inner surface of upper shutter shell 16 a anagainst liner 15 a (not shown in this Figure for clarity). This upwardtranslation of hub 12 allows it to clear the top of spindle 40. However,as a side effect of the upward location of disk 14, the edge of disk 14must be adjusted downwardly to thread the head loading ramps 47 asdescribed more fully below.

[0073]FIG. 15A shows an isometric view of the load ramp in accordancewith the present invention. Load ramp 47 comprises a base 67, head guard61, pivoting arms 60 a and 60 b, abutments 66 a and 66 b, pivot pin 65,and compression spring 69. Each arms 60 comprises a ramped end portion64 and a tail portion 63. Pivoting arms 60 a and 60 b are arranged topivot about pivot pin 65 in opposing fashion between an open position,in which the ramped ends pivot away from each other, and a closedposition in which the ramped ends pivot toward each other. Spring 69 isdisposed between the arms 60 a and 60 b such that the arms 60 a and 60 bare biased toward the closed position. Tail portions 63 a and 63 b ofarms 60 a and 60 b, respectively, engage the corresponding abutments 66a and 66 b to restrain the rotational travel of arms 60 a and 60 b whenthey are biased toward the closed position. Base 67 also comprises ahole 70 for attachment to the drive chassis 57 by means of a screw orother common attachment means. Head guard 61 extends out from the base67 and provides opposing surfaces 61 a and 61 b. Each surface 61 a and61 b has a ramped front portion 62 a and 62 b, respectively. Each ofthese surfaces 61 a and 61 b provides a surface for heads 46 to restwhen the actuator 49 is in the parked position.

[0074] Referring now to FIGS. 15B and 15C, side views of load ramp 47are shown. In FIG. 15B, pivot arms 60 a and 60 b are in the openposition, with spring 69 compressed (by load beams 44, which are notshown for clarity). Accordingly, the distance between ramped endportions 64 a and 64 b is maximized. With the distance thus maximized,media 14 entering between the end portions 64 a and 64 b has sufficientspace to fluctuate during loading without a collision between media 14and load ramp 47. In FIG. 15C, the pivot arms 60 a and 60 b are in theclosed position. Once the media is fully inserted into drive 50,pivoting arms 60 a and 60 b can safely close over media 14 withoutdamage to media 14. With arms 60 a and 60 b in the closed position,heads 46 can safely move between media 14 and load ramps 47.

[0075] Because hub 12 and disk 14 are translated upwardly from hub 12sliding over chassis 57. When hub 12 is compressed into liner 15 a, disk14 is forced out of plane. Forcing disk 14 out of plane in this waycauses a large distortion at outer peripheral edges of disk 14. The edgedistortion, in turn, could cause disk 14 to travel over the top of loadramp end portions 64 rather than properly threading between end portions64 a, 64 b. An adjustment to the disk 14 at the disk access opening isnecessary to ensure that disk 14 properly threads between load ramps endportions 64 a and 64 b.

[0076] Accordingly, referring now to FIG. 16, a isometric bottom view ofupper shutter shell half 16 a with attached liner 15 a is shown. Liner15 a is attached to the inner surface 216 a of shutter half 16 a. Liner15 a is cut around post hole 316 a exposing a portion of inner surface216 a (about the size of drive access hole 316 b). Distortionneutralizer 11 is disposed on surface 216 a of shutter half 216 aproximate the apex of wedge-shaped disk access opening 416 a. (See alsoFIG. 7). Media distortion neutralizer 11 comprises a raised surface oninner surface 216 a. The raised surface can be formed by attachingmaterial to surface 216 a. The thickness of the distortion neutralizeris at least one thickness of liner 15 a and no thicker than about halfthe thickness of the space between shutter shell halves 16. Mostpreferably, it is about 0.2 mm thick. The width of distortionneutralizer 11 is limited by the relatively small size of the presentcartridge 10. That said, it is further limited by the distance betweenthe edge of disk access opening 416 a and hub 12. Accordingly, the widthis between about 1 and 2 mm, preferably about 1.5 mm. Preferably, theraised surface is formed by stamping the distortion neutralizer directlyinto upper shell half 216 a. Moreover, shell liner 15 a is preferablyattached over the top of the raised surface to protect disk 14 fromdirect metal contact on media distortion neutralizer 11. Mediadistortion neutralizer 11 is preferably arced, more preferably the arcis a portion of a circle so as to be concentric with disk 14; however,it could also be substantially straight. Thus, when cartridge 10 isassembled, media distortion neutralizer provides a ridge of materialprojecting downwardly from an upper surface of cartridge 10. Thisprojecting surface ensures that disk 14 is forced downwardly toward thea plane proximately more centered between upper and lower cartridgehalves 18 a, 18 b. The more centered disk 14, therefore, more reliablythreads between head load ramp ends 64 during cartridge insertion intodrive 50.

[0077] The above description of preferred embodiments is not intended toimpliedly limit the scope of protection of the following claims. Thus,for example, except where they are expressly so limited, the followingclaims are not limited to applications involving cartridges for diskdrive systems.

What is claimed is:
 1. A disk cartridge for use in a removable mediadisk drive, said cartridge comprising: an outer shell having a drivingaccess opening and a head access opening, said outer shell having athickness less than about 0.10 inches and a width less than about 2inches; a flexible media adapted for rotation within said drive; a hubfixed to said media proximate the center thereof, said hub beingdisposed in said driving access opening.
 2. The disk cartridge asrecited in claim 1 , further comprising a shutter for selective movementover said head access opening, wherein said outer shell comprises sheetsteel and wherein said shutter comprises aluminum.